The data for this assignment come from the Hospital Compare web site (http://hospitalcompare.hhs.gov) run by the U.S. Department of Health and Human Services. The purpose of the web site is to provide data and information about the quality of care at over 4,000 Medicare-certified hospitals in the U.S Thidataset essentially covers all major U.S. hospitals. This dataset is used for a variety of purposes, including determining whether hospitals should be fined for not providing high quality care to patients (see http://goo.gl/jAXFX for some background on this particular topic).
#2 Finding the best hospital in a state
Write a function called best that take two arguments: the 2-character abbreviated name of a state and an outcome name. The function reads the outcome-of-care-measures.csv file and returns a character vector with the name of the hospital that has the best (i.e. lowest) 30-day mortality for the specified outcome in that state. The hospital name is the name provided in the Hospital.Name variable. The outcomes can be one of \heart attack", \heart failure", or \pneumonia". Hospitals that do not have data on a particular outcome should be excluded from the set of hospitals when deciding the rankings.
Handling ties. If there is a tie for the best hospital for a given outcome, then the hospital names should be sorted in alphabetical order and the first hospital in that set should be chosen (i.e. if hospitals \b", \c", and \f" are tied for best, then hospital \b" should be returned).
The function should use the following template.
best <- function(state, outcome) { Read outcome data Check that state and outcome are valid Return hospital name in that state with lowest 30-day death rate }
The function should check the validity of its arguments. If an invalid state value is passed to best, the function should throw an error via the stop function with the exact message \invalid state". If an invalid outcome value is passed to best, the function should throw an error via the stop function with the exact message \invalid outcome".
Here is some sample output from the function.
source("best.R") best("TX", "heart attack") [1] "CYPRESS FAIRBANKS MEDICAL CENTER" best("TX", "heart failure") [1] "FORT DUNCAN MEDICAL CENTER" best("MD", "heart attack") [1] "JOHNS HOPKINS HOSPITAL, THE" best("MD", "pneumonia") [1] "GREATER BALTIMORE MEDICAL CENTER" best("BB", "heart attack") Error in best("BB", "heart attack") : invalid state best("NY", "hert attack") Error in best("NY", "hert attack") : invalid outcome
Write a function called rankhospital that takes three arguments: the 2-character abbreviated name of a state (state), an outcome (outcome), and the ranking of a hospital in that state for that outcome (num).
The function reads the outcome-of-care-measures.csv le and returns a character vector with the name of the hospital that has the ranking speci ed by the num argument. For example, the call rankhospital("MD", "heart failure", 5) would return a character vector containing the name of the hospital with the 5th lowest 30-day death rate for heart failure. The num argument can take values \best", \worst", or an integer indicating the ranking (smaller numbers are better). If the number given by num is larger than the number of hospitals in that state, then the function should return NA. Hospitals that do not have data on a particular outcome should be excluded from the set of hospitals when deciding the rankings.
Handling ties. It may occur that multiple hospitals have the same 30-day mortality rate for a given cause of death. In those cases ties should be broken by using the hospital name. For example, in Texas (\TX"), the hospitals with lowest 30-day mortality rate for heart failure are shown here.
head(texas) Hospital.Name Rate Rank 3935 FORT DUNCAN MEDICAL CENTER 8.1 1 4085 TOMBALL REGIONAL MEDICAL CENTER 8.5 2 4103 CYPRESS FAIRBANKS MEDICAL CENTER 8.7 3 3954 DETAR HOSPITAL NAVARRO 8.7 4 4010 METHODIST HOSPITAL,THE 8.8 5 3962 MISSION REGIONAL MEDICAL CENTER 8.8 6
Note that Cypress Fairbanks Medical Center and Detar Hospital Navarro both have the same 30-day rate (8.7). However, because Cypress comes before Detar alphabetically, Cypress is ranked number 3 in this scheme and Detar is ranked number 4. One can use the order function to sort multiple vectors in this manner (i.e. where one vector is used to break ties in another vector).
The function should use the following template.
rankhospital <- function(state, outcome, num = "best") { Read outcome data Check that state and outcome are valid Return hospital name in that state with the given rank 30-day death rate }
The function should check the validity of its arguments. If an invalid state value is passed to best, the function should throw an error via the stop function with the exact message \invalid state". If an invalid outcome value is passed to best, the function should throw an error via the stop function with the exact message \invalid outcome".
Here is some sample output from the function.
source("rankhospital.R") rankhospital("TX", "heart failure", 4) [1] "DETAR HOSPITAL NAVARRO" rankhospital("MD", "heart attack", "worst") [1] "HARFORD MEMORIAL HOSPITAL" rankhospital("MN", "heart attack", 5000) [1] NA
Save your code for this function to a file named rankhospital.R. Use the submit script provided to submit